1. Field of the Invention
The present invention relates to an automatically operated fire extinguishing system for either an electric o gas range and particularly concerns such a system associated with the hood over the range. More particularly, the system of the present invention extinguishes fire on the surface of the range and at the same time deactivates the electrical or gas source of energy to prevent the fire from re-starting.
2. General Background
Automatically operated fire extinguishing systems heretofore known for use in conjunction with ranges have generally been concerned with extinguishing a fire due to burning fat or grease in a cooking utensil. Such systems were solely concerned with extinguishing the fire and no provision was made for turning off the electric or gas burners of the range. Frequently the fire extinguishing system extinguished the lighted burners of a gas stove which only served to create a very hazardous condition by permitting fuel (gas) to flow freely from the burners into the atmosphere. When the system extinguished a fire over an electric range, the burners were left energized to reignite spilled grease and fat. No provision was made for automatically exhausting smoke and fumes generated during the fire and while it was being extinguished. Also, no provision was made for sounding an audible alarm. Inadequate provision was made for operating the entire system manually in lieu of or in addition to automatic operation. Further no provision was made to prevent a false engagement of the system. Even in some systems which automatically operated the fire extinguishing apparatus and deactivated the source of electricity or gas failed to provide a means to prevent a false activation of the system in the event of a momentary power outage.
Several attempts have been made in the prior art to develop a system for automatically extinguishing fires.
U.S. Pat. No. 3,463,233 issued to W. M. Haessler entitled "Method Of Extinguishing Deep Fat Fires" discloses, as best seen in its FIG. 1, a device providing a fire extinguishing system with mechanical means (35) for deactivating the range's power supply and, thereafter preventing its resumption upon actuation of the fire extinguisher. The shut-off switch is applicable to either gas or electric ranges.
U.S. Pat. No. 3,772,499 issued to D. E. Fritzsche entitled "Fryer Circuit For Use With A Hood Circuit Having Fire Protection Apparatus" discloses a device providing a fusible mechanical link (21) which at a predetermined temperature breaks and activates a switching means (20) that opens a circuit (11) thus deactivating the power source for the range and thereafter preventing its resumption and activates a fire extinguishing means.
U.S. Pat. No. 3,824,374 issued to E. J. Mayher entitled "Condition Responsive Disconnect Arrangement For Electrical Cooking Equipment" discloses a thermostat, safety circuit and contactor across an electrical power source (24) with the contactor (30) operating when energized to connect the heating the element (18) across the power source. The safety circuit includes a normally closed switch (38) actuated in response to a sensed abnormal condition to open the circuit thereby shutting off the power supply to the range and thereafter preventing its resumption and activating a source of carbon dioxide (44).
U.S. Pat. No. 3,653,443 issued to W. E. Dockery entitled "Fire Extinguishing System For Cook Stoves and Ranges" discloses means or shutting off a gas or electric range and thereafter preventing its resumption and activating a fire extinguishing system.
Other typical prior art patents include U.S. Pat. Nos. 3,283,827 issued to D. A. Diehl; 4,256,181 issued to C. C. Searcy; 4,524,835 issued to F. V. Mingrone; 4,356,870 issued to E. C. Gaylord; and, 4,066,064 issued to E. B. Vandas.
The present invention is directed to overcoming the above and other shortcomings, deficiencies, objects and disadvantages of prior systems employed for extinguishing fires on ranges and in hoods over the ranges.
According to the present invention, a removable and rechargeable fire extinguisher is installed remotely from an electric or gas range. Strategically located heat sensors on the hood of the range are connected in a circuit with means for breaking the circuit for the electrical lines energizing the burners of the electric range. Where a gas range is employed, the heat sensors are connected in circuit with a solenoid operated valve for turning off the gas supplied to the range. Also connected in circuit with the heat sensors are solenoid operated valves which turn on the fire extinguisher at pre-determined temperatures to discharge gaseous or liquid fire extinguishing agents around the hood and on the range. An exhaust fan may be provided in the system arranged to turn on automatically for exhausting fumes and smoke. Automatically operated audible alarms are also provided.